Date: Jan 25, 2013 3:37 AM
Author: David Bernier
Subject: Re: inbreeding as a species-accelerant ; NOVA "Decoding Neanderthal"<br> #198 Rockthrowing theory book
On 01/25/2013 01:39 AM, Archimedes Plutonium wrote:> Basically I am just simply asking for what mathematical advantage for> mutations arises for inbreeding. I do not know if any biologist has> researched this question. The question of how much faster or how much> more mutations accrue when a population of a species has inbreeding.> Such as when 1 male and 1 female are stranded on a island and up to> those 2 individuals to keep their kind growing. So there is much> inbreeding. And not outside mating. So that all generations on the> island trace their ancestors back to those starting 2.>> Compare that population with an equal sized population that has no> inbreeding.>> I would hazard to guess that the mutations of the inbreeding> population would be far ahead of the non inbreeding population.>> And I think this is how so many islands that are isolated from their> mainland have so many different species that the mainland does not> have, is because of what I call the species accelerant of inbreeding.>> So that Neanderthal was two Africans that migrated north out of Africa> some 400,000 years ago and because of inbreeding ended up as different> species of the Africans who migrated enmasse some 60,000 years ago.>> So that the Clovis man who migrated to the Americas, either out of> Asia or Europe some 15,000 years ago, if Clovis man had been a single> 1 male and 1 female and populated the Americas, that by the time of> Columbus would have found, not the same species of Homo sapiens, but> perhaps a different species. So here we have a sort of scientific> prediction or question, of how many Clovis people migrated to the> Americas some 15,000 years ago so that their genetic stock was> sufficient to not mutate too much so that by the time Columbus> arrived, they would still be the same Homo sapiens species.>> So we need some biology research into what sort of mutation rate is> increased in populations with inbreeding versus populations of> noninbreeding.>> And in sociology we can recognize the problem of the American Indians> in that they needed tribal interactions with other diverse tribes> because of inbreeding.>> Usually inbreeding brings out deleterious mutations, and rarely does> it bring out advantageous mutations.>> Now I would be deeply surprised if no biologist has done research on> this before, of extracting a number for mutation rate in a> noninbreeding population and a mutation rate in a inbreeding> population.>> So if we had such a numbers figure for this mutation accelerant and> applied that numbers to Clovis Man, we may be able to roughly estimate> how many individuals, male and female crossed over into the Americas.[...]

Some common genetic diorders are single-gene recessive,meaning that one good allele and one bad allelemakes for an Ok baby (a carrier), but two badalleles makes for a "bad" baby who exhibits or manifeststhe disease linked to the "bad allele".

And two good alleles makes an Ok baby also.

That's for the genes carried on the non-sexual chromosomes.For diseases single gene recessive on the X sexualchromosome, one allele bad of the gene on the X-chromosomemakes for a "bad baby" if it's male, cause the male hasone X and one Y sex-chromosome. But a female baby withtwo X-chomosomes and 1 good and 1 bad allele would bean Ok baby, but still a carrier. This happens withhemophilia, if memory serves me well.

The genes that make for a strong baby who will reproducewith optimal number of off-spring is highly non-trivial.

Some game theory could be involved and there could be severaloptimal fitness genomes; also, variation of gene pool could bean asset for a loosely-bound tribe.

Maybe some models can say something about the optimal strategyfor an individual, like say considering marrying a second-cousinby age 37 if all else fails. It's just speculation on my partthat such studies/simulations/models exist.